Background/Purpose:

Most rheumatoid arthritis (RA) patients (pts) who respond to the first course of RTX need retreatment with a second course after 6 to 12 months due to increase in disease activity. However, some pts show a sustained clinical response for a longer period. Our objective was to characterize pts who showed a sustained response after the 1st course of RTX and compare them to those who were not long-term responders.

Methods:

10 European biologics registries provided anonymized data sets of RA pts treated with RTX in clinical practice for analysis of pooled data. Pts with available retreatment data were eligible for the current analyses. Long-term response was defined as no retreatment during the 1st year AND sustained response (DDAS28 < -1.2 vs. baseline) at months 612, in pts with at least 9 months follow-up. The comparator groupincluded pts retreated during the 1st year and/or without sustained response. Baseline (BL) characteristics, and year 1 and year 2 DAS28 states and changes were compared. Due to heterogeneity in timing of follow-up visits, overall mean DAS28 was calculated for the period 312 months and for year 2. The main effectiveness outcome was mean DAS28 during year 2. Predictors of long-term response were identified by univariate and multivariate logistic regression analysis.

Results:

209 pts were classified as long-term responders (LTRs) and 867 were non-long-term responders (NLTRs) (79% of NLTRs were retreated during the 1st year); 93% vs. 88% had >18 months follow-up time. In both groups, 83% were female, 81% received concomitant DMARDs and mean disease duration was 12 years. 84%/82% were RF pos. LTRs were significantly older (mean 55.1 vs. 52.2 years, p=0.005), were more often biologics naïve (51.0% vs. 40.4%, p=0.006) and had higher BL DAS28. Despite higher BL DAS28, % in low disease activity state (LDA) and remission (rem) were higher for LTRs through year 1, and mean DAS28 was lower (Table 1). The difference in mean DAS28 was more or less sustained through year 2, but % in LDA/rem. were similar for most time points. 34% of LTRs were retreated during year 2. Mean(SD) total number of RTX courses from baseline through year 2 was 1.6(1.0) for LTRs vs. 2.6(0.8) for NLTRs (p<0.001). Older age, biologics naivety, higher BL DAS28 and lower HAQ-DI were independent predictors of LTR (Table 2).

Conclusion:

Biologics naïve pts who were older and who had higher disease activity and less functional impairment at baseline were more likely be long-term responders to the 1st course of RTX, and these pts generally sustained a good clinical response through year 2.